<a href="" ng-click="row.toggleExpand($event, true)" class="toggle-expand-link">
  <span ng-if="row.expanded">
    <span class="fa fa-angle-down" aria-hidden="true"></span>
    <span class="sr-only">Collapse</span>
  </span>
  <span ng-if="!row.expanded">
    <span class="fa fa-angle-right" aria-hidden="true"></span>
    <span class="sr-only">Expand</span>
  </span>
</a>
